Measuring the driving distance covered by a vehicle is normally accomplished by a driving distance counter (odometer), whose reading is displayed to the driver. The recorded travel distance is usually calculated on the basis of wheel rotation and transmission revolution information and reflects the distance driven by the vehicle. This distance represents a measure of the wear of the vehicle and its components. The driven distance constitutes essential information for ascertaining the residual value of a used vehicle. There are conventional devices which display a remaining time as estimated travel distance until the next required vehicle inspection as a function of the current wear of the vehicle.
In the case of vehicles equipped with a “sailing functionality”, in particular what is known as start-stop sailing, that is to say, an expanded sailing functionality in which the combustion engine is switched off during the sailing operation, this conventionally determined driving distance may deviate considerably from the distance covered by the internal combustion engine as drive. In such vehicles the internal combustion engine has mostly driven “less travel distance” than the vehicle. Although this circumstance is usually correctly taken into account during the vehicle inspection, it is not made available to the end user in the form of direct information. Depending on the user driving cycle, sailing components of up to 30% of the total driving distance have been observed in vehicle testing, i.e., the odometer implies a driving output of the engine that is up to 30% higher.
An example method in accordance with the present invention allows a measurement of an engine driving output that characterizes the engine load of a drive motor of a vehicle. Here, at least one parameter which characterizes the engine load is allocated a driving distance equivalent. The driving distance equivalent is continuously incremented in an odometer and displayed to the driver. The indication of a separate engine driving output which characterizes the engine load constitutes interesting information for the driver of the vehicle and, for instance, may be used for obtaining a higher residual value of a vehicle equipped with the sailing functionality in the event of a resale, for example.
Preferably, a measure of the crankshaft revolutions of the motor of the vehicle is used as parameter characterizing the engine driving output. The crankshaft revolutions represent an easily acquirable measure of the engine load and thus the driving output of the engine.
According to another development of the method, the at least one parameter characterizing the engine driving output is the particular driving distance of the vehicle during which the drive motor is coupled to a drive train of the vehicle. In vehicles equipped with the sailing functionality, for instance, the engine load is able to be measured in a more realistic manner in this way.
Especially preferably, coupling of the drive motor to the drive train is assumed when a clutch is closed without slip or largely without slip, e.g., when the clutch is operated in micro-slip. This state represents the instant at which the measurement of the engine load should usefully be started in vehicles featuring a sailing functionality.
Especially preferably, the driving distance during which the drive motor is coupled to the drive train of the vehicle is interpreted directly as engine driving output. If the vehicle has a sailing functionality, the engine driving output is able to be directly measured via the driven distance when the drive engine is coupled to the drive train.
The engine driving output is advantageously displayed to the driver of the vehicle. This additional information is of use to the vehicle driver in order for inferring the engine load and thus the engine driving output. The engine driving output is advantageously displayed to the driver in addition to the conventionally displayed driving distance.
An example device in accordance with the present invention for ascertaining an engine load of a drive motor of a vehicle includes a device for acquiring at least one parameter that characterizes the engine load, and a conversion device, by which an engine load is able to be converted into a driving distance equivalent.
The device for acquiring at least one parameter characterizing the engine load preferably includes one or more of the following sensor(s): a rate-of-rotation sensor or a clutch sensor for detecting the operating state of a clutch, by which the drive engine is able to be coupled to a drive train.
According to one advantageous specific embodiment, the conversion device has a driving distance counter which can be connected or disconnected as a function of a switching signal. In this way a driving distance equivalent of the engine load is able to be measured directly.
An example computer program in accordance with the present invention allows the example method according to the present invention to be implemented in an existing control unit without structural changes being required. It carries out all of the steps of the method according to the present invention when it is running on a computer device or a control unit. Retroactive fitting is possible as well.